SOLUTION: Please help me solve this problem... i need it rn When john and marsha worked together, they finished a job in 10 days. But when she joined him only after he had worked for 7 da

Question 1104609: Please help me solve this problem... i need it rn
When john and marsha worked together, they finished a job in 10 days. But when she joined him only after he had worked for 7 days, they finished the same job in 5 more days. In how many days can each of them finish the job alone?
a.Representation

B.formulate the equation
C. Show the solution
D. Checking

Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
When john and marsha worked together, they finished a job in 10 days. But when she joined him only after he had worked for 7 days, they finished the same job in 5 more days. In how many days can each of them finish the job alone?
a.Representation
Together:: time = 10days/job ; rate = 1/10 job/day
John:: time = j days/job ; rate = 1/j job/day
Marsha:: time = m days/job ; rate = 1/m days/job
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B.formulate the equation
rate + rate = together rate
1/j + 1/m = 1/10
7(1/j) + 5(1/10) = 1
---
7/j = 1/2
j = 14 days/job (John's time to finish alone)
---
(1/14) + 1/m = 1/10
1/m = (1/10) - (1/14)
1/m = (14-10)/140
m = 140/4 = 35 (Marsha's time to finish alone)
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Cheers
stan H.
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C. Show the solution
D. Checking
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